Behavior disorders, including aggression and self-injury, can cause considerable suffering for individuals with intellectual and developmental disabilities (IDD) and their care givers, as well as result in significant added costs to an already overburdened health care system. Such disorders, here termed Chronic Aberrant Behavior (CAB), have been effectively treated using procedures, provided by the field of Behavior Analysis, that are based on translational studies of operant learning principles. The purposes of this proposed program of research are to extend both the conceptual basis and range of treatment options for CAB of persons with IDD. Among the noteworthy aspects of this proposed program of research are that studies will be carried out by investigators known for the study and treatment of CAB and at three separate centers of excellence (i.e., three current IDDR Centers recognized as leaders in innovation and outstanding accomplishments for several decades). Such an approach to multi-site research has only been practical in the past few years with the dramatic advances in computer technology and telecommunications. Selection of investigators and sites can thus now be based on matching the experimental resources. Investigations conducted across the three research centers and four sites will focus on: (1) Examining the role of incentive shifts in triggering CAB and the development of interventions based on this novel conceptual framework; (2) Applying principles of behavioral economics to influence the choice of alternative constructive activities rather than CAB; and (3) Promoting generalization of therapy gains across settings, people and circumstances. An Administrative Core and Methodological Integrity Core will support the proposed research. Evidence arising from this multi-site, multi-faceted approach to the treatment of CAB in IDD will make it possible to design better therapeutic individuals with IDD to lead better lives.